Use of corticosteroids during treatment in dogs infected with Dirofilaria immitis: is it a risk or a benefit?

Abstract

D-dimer, a biomarker resulting from fibrin degradation, is a key protein used in the diagnosis of pulmonary thromboembolism (PTE). PTE is a life-threatening complication in dogs infected with Dirofilaria immitis. However, thereare conflicting results regarding the effect of glucocorticoid therapy on these patients. This study aims to investigatethe effects of low dose of corticosteroids on D-dimer levels in dogs with heartworm disease before, during, and afteradulticide therapy. Sera of 48 dogs with D. immitis undergoing adulticide therapy were evaluated on days 0, 30, 60, and 90. Additionally, parasite burden, presence of pulmonary hypertension, and microfilariae were assessed on day 0. Of them, 19 dogs (group B) received prednisone at decreasing doses (starting 0.5 mg/kg/BID) from day 0 during all study. Dogs not receiving corticosteroids (group A) showed higher D-dimer concentrations on day 0 (0.13±0.15 μg/mL), which decreased on day 30 (0.10±0.04 μg/mL) and remained similar thereafter. Dogs receiving corticosteroids started with slightly lower D-dimer concentrations (0.09±0.00 μg/mL), which remained at similar levels to group A for the rest of the study. D-dimer levels were found to be higher in older dogs, in dogs with high parasite burden, presence of microfilariaeor symptoms, but not with pulmonary hypertension. There were no statistically significant fluctuations of D-dimervalues between groups, suggesting that there was no increased risk of PTE due to the use of corticosteroids duringadulticide treatment. The results showed that the use of anti-inflammatory doses of corticosteroids did not produce significant variations in D-dimer concentrations during the adulticide treatment, contradicting previous results. Furthermore, anti-inflammatorydoses of prednisone improved general symptoms, reduced local inflammation at the melarsomine inoculation site, andcontributed to a faster recovery. Therefore, the benefits of corticosteroid administration may outweigh the potentialrisks, although further studies with larger sample sizes are necessary to confirm these findings.